//
// detail/null_event.hpp
// ~~~~~~~~~~~~~~~~~~~~~
//
// Copyright (c) 2003-2022 Christopher M. Kohlhoff (chris at kohlhoff dot com)
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//

#ifndef ASIO_DETAIL_NULL_EVENT_HPP
#define ASIO_DETAIL_NULL_EVENT_HPP

#if defined(_MSC_VER) && (_MSC_VER >= 1200)
# pragma once
#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)

#include "asio/detail/config.hpp"
#include "asio/detail/noncopyable.hpp"

#include "asio/detail/push_options.hpp"

namespace asio {
    namespace detail {

        class null_event
                : private noncopyable {
        public:
            // Constructor.
            null_event() {
            }

            // Destructor.
            ~null_event() {
            }

            // Signal the event. (Retained for backward compatibility.)
            template<typename Lock>
            void signal(Lock &) {
            }

            // Signal all waiters.
            template<typename Lock>
            void signal_all(Lock &) {
            }

            // Unlock the mutex and signal one waiter.
            template<typename Lock>
            void unlock_and_signal_one(Lock &) {
            }

            // Unlock the mutex and signal one waiter who may destroy us.
            template<typename Lock>
            void unlock_and_signal_one_for_destruction(Lock &) {
            }

            // If there's a waiter, unlock the mutex and signal it.
            template<typename Lock>
            bool maybe_unlock_and_signal_one(Lock &) {
                return false;
            }

            // Reset the event.
            template<typename Lock>
            void clear(Lock &) {
            }

            // Wait for the event to become signalled.
            template<typename Lock>
            void wait(Lock &) {
                do_wait();
            }

            // Timed wait for the event to become signalled.
            template<typename Lock>
            bool wait_for_usec(Lock &, long usec) {
                do_wait_for_usec(usec);
                return true;
            }

        private:
            ASIO_DECL static void do_wait();

            ASIO_DECL static void do_wait_for_usec(long usec);
        };

    } // namespace detail
} // namespace asio

#include "asio/detail/pop_options.hpp"

#if defined(ASIO_HEADER_ONLY)
# include "asio/detail/impl/null_event.ipp"
#endif // defined(ASIO_HEADER_ONLY)

#endif // ASIO_DETAIL_NULL_EVENT_HPP
